Axle drive

ABSTRACT

An axle drive for a vehicle comprising at least one drivable vehicle axle oriented transversely to a longitudinal direction of the vehicle comprises: a drive shaft that extends in parallel with the longitudinal direction and that is configured to receive drive power from an electric motor at an input section and to output said drive power at an output section; a driven shaft that extends in parallel with the drive shaft and that is configured to receive drive power from the output section of the drive shaft at an input section and to output said drive power to the vehicle axle via a bevel gear arranged at a first end of the driven shaft; and a brake, in particular a parking brake, having a brake disk that is arranged at a second end of the driven shaft and that is arranged between the input section of the drive shaft and the input section of the driven shaft with respect to the longitudinal direction.

The invention relates to an axle drive for a vehicle comprising at leastone drivable vehicle axle oriented transversely to a longitudinaldirection of the vehicle.

Such an axle drive may, for example, be arranged at a front axle or at arear axle of a vehicle in order to at least partly transmit drive powerreceived from a motor to a drivable vehicle axle and to set the vehicleinto motion. In this respect, an axle drive may have at least one shaftthat transmits the received drive power to the vehicle axle, for whichpurpose the shaft may, for example, be rotationally effectively coupledto the vehicle axle via a bevel gear. In order furthermore to be able todrive the vehicle axle at a desired rotational speed or to be able toapply a required torque, an axle drive may, for example, have aplurality of shafts that are connected to one another via at least onegear stage. This may make it possible to transmit a rotational speed ora torque generated by a motor in a manner adapted to a respectivevehicle or to a respective operating situation.

However, there is generally the problem with an axle drive that theinstallation space in the region of the vehicle axle or beneath thevehicle is very limited and a compact design of the axle drive istherefore required. Accordingly, it is always endeavored both to limitthe number of components of the axle drive and to achieve asspace-saving arrangements as possible of these components. However, itmay be necessary or desired to configure an axle drive with a brake andin particular a parking brake to be able to provide a parking functionand ensure a safe standstill of the vehicle such that an unwantedrolling away, for example while the vehicle is parked, may be ruled outas far as possible. In particular in commercial vehicles, for example,trucks, fork-lift trucks or dump trucks, such brakes may be necessary tobe able to reliably prevent a movement or a rolling away of the vehicleduring a loading. Such a brake may also satisfy an emergency brakingfunction in addition to the typical service brakes of the vehicle, inparticular when it automatically closes on a drop in the operatingpressure. However, the configuration of an axle drive with a brake isusually accompanied by a corresponding increase in the installationspace occupied by the axle drive. Such brakes may in particular beconfigured with brake disks that may frequently have a relatively largeextent or a large diameter in order, in particular in the case of heavyvehicles, for example commercial vehicles that are loaded or to beloaded, to be able to develop a sufficient braking effect for stoppingthe vehicle. However, this increase of the axle drive may, due to thelimited installation space in the region of the vehicle axle, make theinstallation of such an axle drive comprising a brake more difficult orpreclude it.

In addition to this expansion of the axle drive by a configuration witha brake disk, the problem in particular arises on the use of electricmotors for transmitting drive power that the required electric motors,which are likewise of compact design, often generate very highrotational speeds and the brake disk may thus likewise be accelerated tohigh rotational speeds during a trip with the vehicle. This may, inparticular in view of the usually large diameter of such brake disks,lead to unwanted vibrations of the brake disk and to a noise generationthat is thereby caused and that has a disadvantageous effect on thedriving comfort and that may possibly also result in instabilities ofthe axle drive or of the drive train of the vehicle.

It is therefore an object of the invention to provide an axle drivecomprising a brake, in particular a parking brake, said axle driveenabling the reception of drive power from fast-rotating electric motorswith an improved acoustic behavior of a brake disk of the brake andhaving a very compact design.

This object is satisfied by an axle drive having the features of claim 1and in particular in that the axle drive comprises a drive shaft thatextends in parallel with the longitudinal direction of the vehicle andthat is configured to receive drive power from an electric motor at aninput section and to output said drive power at an output section; inthat the axle drive comprises a driven shaft that extends offset fromthe drive shaft in parallel with the longitudinal direction of thevehicle between a first end and a second end opposite thereto and thatis configured to receive drive power from the output section of thedrive shaft at an input section and to output said drive power to thevehicle axle via a bevel gear arranged at the first end; and in that theaxle drive comprises a brake, in particular a parking brake, having abrake disk that is arranged at the second end of the driven shaft andthat is arranged between the input section of the drive shaft and theinput section of the driven shaft with respect to the longitudinaldirection of the vehicle. The vehicle axis is in this respect orientedtransversely, in particular at least substantially perpendicular, to thelongitudinal direction of the vehicle.

Since the drive shaft and the driven shaft are aligned in parallel withthe longitudinal direction of the vehicle, the extent of the axle drivemay also be concentrated along this longitudinal direction and may thususually be concentrated in the direction of the greatest extent of thevehicle. The extent of the axle drive in parallel with the vehicle axlemay, in contrast, be minimized such that, for example, the space betweentwo wheels arranged at the ends of the vehicle axle may be kept free asfar as possible and the axle drive does not impair or limit a deflectionof the wheels.

In this respect, the input section of the drive shaft, which is providedfor receiving drive power, may in particular be an end section of thedrive shaft that may, for example, be formed by a flange or be connectedto a flange to be able to connect an electric motor or its motor shaft.The drive shaft may in this respect be formed in one part such that theelectric motor may be directly connected to the input section of thedrive shaft, for example via a flange, to transmit drive power to theinput section and the drive shaft. Furthermore, it is also possible forthe drive shaft to comprise a plurality of part shafts, which may, forexample, be rotationally fixedly connected to one another via plug-inconnections, such that a rotation may be transmitted between the partshafts without changing the rotational speed. The input section of suchmulti-part drive shafts is in this respect likewise given by thatsection which the electric motor directly adjoins or at which a cleardeflection of the drive power flow, which deflection is in particularnot based on production tolerances, from a direction in parallel withthe longitudinal direction of the vehicle takes place. In general, amotor shaft that extends out of an electric motor and that is at leastsubstantially coaxially connected to a further part shaft of the driveshaft within the axle drive may thus in particular also be regarded as apart shaft of the drive shaft and have its input section.

Since the brake disk of the brake, which may in particular berotationally fixedly connected to the driven shaft at the second end, isarranged between the input section of the drive shaft and the inputsection of the driven shaft, a high integration of the brake disk intothe axle drive takes place and the brake disk does not cause a relevantincrease in the axle drive along the longitudinal direction. Due to theparallel offset between the drive shaft and the driven shaft, a brakedisk having a radius corresponding at least approximately to this offsetmay further be arranged at the driven shaft, wherein the installationspace additionally occupied by the axle drive in a radial direction withrespect to the driven shaft for attaching the brake disk onlyapproximately corresponds to the single radius of the brake disk in thisrespect. Thus, relatively large brake disks for holding heavy vehiclesor for applying large torques may also be arranged in a space-saving andcompact manner. In this respect, the brake disk may, for example, bedirectly attached to the driven shaft or may be rotationally effectivelyor brake-effectively connected to the driven shaft via a holder.

Furthermore, the configuration of the axle drive with two shafts offsetin parallel from one another makes it possible to use the driven shaftin the manner of a countershaft such that a speed reduction stage may inparticular be provided between the output section of the drive shaft andthe input section of the driven shaft and a rotation of the drive shaftmay be transmitted in a speed-reduced or slowed-down manner to thedriven shaft. The rotational speed level of the brake disk may therebyalso be lowered relative to the drive shaft such that compact andfast-rotating electric motors may be used to provide the drive powerwithout the brake disk also being subjected to such fast rotations. Anoise formation due to vibrations of the brake disk at high rotationalspeeds and possible instabilities of the axle drive due to suchvibrations may thus be avoided and the acoustic behavior of the brakedisk or of the axle drive may be improved.

The brake may in particular act as a parking brake and may be providedto reliably secure the vehicle against rolling away when stationary. Forthis purpose, the brake may, for example, have a brake caliper thatengages around the brake disk and that may be configured to hold thebrake disk when the vehicle is stationary in order to block a rotationof the brake disk, of the driven shaft connected thereto, and thus alsoof the vehicle axle coupled to the driven shaft via the bevel gear. Inthis respect, the brake caliper may in particular engage at a section ofthe brake disk that is a radially outer section with respect to thedriven shaft to be able to apply as large a braking torque as possibleor to be able to compensate as large a torque as possible that usconducted via the vehicle axle to the driven shaft.

Alternatively or additionally to such a brake serving as a parkingbrake, provision may also be made to equip the axle drive with anemergency braking function through the brake. For example, a brakecaliper may be able to be actively brought out of engagement with thebrake disk during a driving with the vehicle in order to enable arotation of the brake disk together with the driven shaft, while, on anabsence of the required action or of a signal necessary therefor, thebrake caliper may automatically come into engagement with the brake diskto brake the vehicle. For this purpose, the brake caliper may inparticular comprise a piston that may be acted on or is acted on bypressure during the travel, wherein the brake caliper may automaticallycome into engagement with the brake disk on the absence of the pressureacting on the piston. On a possible failure of a vehicle system or of amotor providing energy for generating the pressure, for example of theelectric motor for driving the vehicle axle, an engagement of the brakecaliper into the brake disk and a braking of the vehicle resultingtherefrom may thereby be automatically achieved such that the vehiclemay be reliably secured against such failures and may quickly be broughtto a standstill in emergency situations. Such a brake provided as anemergency brake may generally also be used or understood as a parkingbrake in that the action for releasing the brake caliper may inparticular also be deliberately omitted when the vehicle is stationaryin order to secure the vehicle against rolling away in the sense of aparking brake.

Provision may be made that the drive shaft is configured to directlyreceive drive power from an electric motor at the input section, forexample via a flange. However, an indirect transmission may also beprovided such that the drive power output by the electric motor may, forexample, be transmitted to the input section of the drive shaft via gearstages or deflections. Similarly, the output of the drive power at theoutput section, which may in particular be an end section of the driveshaft, may take place directly or indirectly to the input section of thedriven shaft. For this purpose, one or more spur gear sets may, forexample, be provided between the drive shaft and the driven shaft, bywhich spur gear sets the offset between said shafts may in particularalso be achieved. In this respect, such a spur gear set may beconfigured such that a rotation of the drive shaft is transmitted in aspeed-reduced or slowed-down manner to the driven shaft.

Furthermore, provision may be made that drive power received from theelectric motor is only partly transmitted to the input section of thedriven shaft at the output section, while a further portion of the drivepower is transmitted elsewhere and is, for example, transmitted to apossibly provided second drivable vehicle axle. Similarly, only aproportional transmission of drive power to the vehicle axle may alsotake place by means of the bevel gear arranged at the first end of thedrive shaft, while a further portion is transmitted elsewhere. Ingeneral, however, the axle drive disclosed herein is configured suchthat drive power received from an electric motor at the input section ofthe drive shaft is at least partly output to the drivable vehicle axlevia the bevel gear arranged at the first end of the driven shaft.

Possible embodiments of the invention can be seen from the dependentclaims, from the description, and from the drawings.

In some embodiments, the axle drive may further comprise a housing inwhich the drive shaft and the driven shaft are received, wherein theoutput section of the drive shaft and the input section of the drivenshaft are arranged within the housing. Consequently, the drive shaft andthe driven shaft may indeed extend partly out of the housing, wherein,however, at least the transmission of the drive power from the outputsection of the drive shaft to the input section of the driven shafttakes place within the housing. In this respect, the bevel gear arrangedat the first end of the driven shaft may in particular be arrangedwithin the housing. In general, the bevel gear may also extend at leastpartly out of the housing to transmit the drive power to the vehicleaxle. Alternatively thereto, the bevel gear may also be arrangedcompletely outside the housing, wherein the driven shaft then extendsout of the housing with its first end.

The driven shaft may in particular extend out of the housing with itssecond end such that the brake disk may be arranged outside the housing.The input section of the drive shaft may also be arranged outside thehousing to enable a connection of an electric motor. Furthermore, thedrive shaft may generally extend beyond the output section in order, forexample, to only partly transmit drive power received at the inputsection via the output section to the input section of the driven shaftand to conduct a further portion of the drive power out of the housing.

Furthermore, in some embodiments, the housing may have a bearing sectionintegrally formed in one part or be formed by a bearing section which isintegrally formed in one part, wherein bearings for supporting the driveshaft and/or the driven shaft are supported at the bearing section. Inthis respect, all the bearings for supporting the drive shaft and/or thedriven shaft may in particular be supported at this bearing sectionintegrally formed in one part.

The support points for supporting the drive shaft and the driven shaftmay be oriented exactly in alignment with one another by a bearingsection integrally formed in one part, which may in particular beconfigured as a single bonded component, to be able to prevent anyinaccuracies or imbalances, in particular on the use of fast-rotatingelectric motors, and to be able to handle the high rotational speeds. Inthis respect, the bearings may in particular be directly supported atthe bearing section. However, provision may also be made that thesupport of at least some of the bearings takes place at a furtherhousing part that may be precisely aligned with the bearing section.Such bearings are in this respect also at least indirectly supported atthe bearing section integrally formed in one part such that the exactpositioning of these bearings may also be ensured on a precise alignmentof the further housing part with the bearing section. In the case ofsuch an indirect support of at least some of the bearings, thesebearings are preferably supported in the radial direction at the bearingsection integrally formed in one part with respect to the axis ofrotation of the respective supported shaft. Accordingly, the furtherhousing part, via which the indirect support takes place, is thereforeradially arranged between the respective bearing and the bearing sectionintegrally formed in one part in the region of the axial extent of thebearing.

For example, provision may be made that a flange section for connectingan electric motor is centered at an outer diameter in an opening of thebearing section, in which the drive shaft is arranged, and is preciselyaligned with the bearing section by a suitable fit selection ortolerance selection. In this respect, the bearings of the drive shaftmay be at least partly supported at the bearing section via this flangesection, which is precisely aligned with the bearing section, such thatthe bearings supported directly at the flange section and indirectly atthe bearing section may nevertheless be arranged exactly in alignmentwith one another or with further bearings of the drive shaft that aredirectly supported at the bearing section. Furthermore, due to a flangesection that is precisely matched to the bearing section, a precisealignment of an electric motor, which may be connected to the flangesection, with the drive shaft may be achieved such that, also due to thecoupling of the drive shaft to an electric motor, no stress forces aretransmitted to the drive shaft in the radial direction and an exactalignment of the drive shaft in parallel with the longitudinal directionof the vehicle may be ensured.

Provision may be made that an inner space of the housing defines acommon oil chamber for the drive shaft and the driven shaft. Due to sucha common oil chamber, a radiation surface for waste heat as large aspossible may be provided, said waste heat being generated within thehousing by the drive shaft, in particular on a connection to afast-rotating electric motor. For this purpose, a speed reduction stagemay furthermore in particular be provided between the drive shaft andthe driven shaft such that the driven shaft rotates slowed down, andcorrespondingly with a smaller heat development, with respect to thedrive shaft. Furthermore, a lubrication, in particular of the bearingsof the shafts, may be achieved without a pump by such a common oilchamber in that the lubrication, for example, takes place via a geardrive and a wiper in a reservoir.

Furthermore, in some embodiments, the axle drive may be configured suchthat the common oil chamber communicates with an axle chamber which isin particular configured as the inner space of an axle housing or of anaxle chamber housing section and into which the bevel gear at leastprojects. The oil chamber may consequently extend beyond the axle driveto be able to achieve a further improved leading off of waste heat.Furthermore, means for lubrication may thereby be arranged at or in theaxle chamber without taking up additional installation space within theaxle drive.

In some embodiments, the brake disk may be arranged outside the housing.In this respect, the brake disk may in particular be arranged completelyoutside the housing and thus also outside said oil chamber such that thebrake may be designed as completely dry. For this purpose, the drivenshaft may extend out of the housing with its second end such that thebrake disk, which is rotationally fixedly connected to the driven shaftat the second end, may be arranged outside the housing. This may inparticular also enable an assembly or dismantling of the brake disk, forexample to replace a worn brake disk, without having to open the housingand having to access an inner space of the housing for this purpose.Furthermore, the configuration of the brake with a dry rotating brakedisk makes it possible to achieve as high as possible an efficiency thatis in particular increased with respect to a wet-running multi-diskbrake.

Provision may be made that the housing extends around the brake disksuch that it axially surrounds a peripheral region of the brake disk atboth sides. In this respect, the housing may in particular have a flangesection for connecting an electric motor, said flange section axiallycovering said peripheral region of the brake disk at least at one side,while the peripheral region may, for example, be covered by said bearingsection at the axially opposite side. Due to such a nested design of thehousing, a compact arrangement of the axle drive may be achieved byintegrating a brake disk, which rotates outside the housing and therebyrotates dry, into the axle drive in as space-saving a manner aspossible. In this respect, an anyway required flange section forconnecting an electric motor may in particular be attached only slightlyaxially offset to be able to insert a peripheral section of a flat brakedisk into the free space that is thereby produced in the axial directionwith respect to the driven shaft and to be able to ideally use the spacebetween the drive shaft and the driven shaft in the radial direction.

A reception recess for the brake disk may be formed at the housing, saidreception recess having two side sections that face radially outwardlywith respect to the drive shaft and that are axially connected to oneanother radially inside, wherein said peripheral region of the brakedisk is arranged between the side sections. In this respect, thereception recess may in particular be formed by respective outer sidesor outer surfaces of the housing such that the reception recess does notextend into an inner space of the housing and the brake disk thus alsodoes not extend into such an inner space, but is arranged completelyoutside the housing despite the arrangement between the side sections ofthe reception recess.

The side sections formed by the housing may further be formed in astraight line, while it is also possible for at least one of the sidesections to have a non-rectilinear structure and, for example, a steppedstructure. With such a non-rectilinear side section, the spacing of theside section from the brake disk in the axial direction with respect tothe driven shaft may consequently change along a radial direction withrespect to the driven shaft. The reception recess may thus beapproximately U-shaped, wherein the radially outwardly extending sidesections do not necessarily form rectilinear limbs of such anapproximately U-shaped reception recess. While the reception recess maybe radially outwardly open in order, for example, to enable an insertionof the brake disk into the reception recess, the reception recess isclosed radially inside by the axial connection of the side sections toone another.

The reception recess may be at least partly formed by a flange sectionof the housing provided for fastening the electric motor to the housing.Such a flange section may in particular form one of said side sectionsand be formed separately or separably from said bearing sectionintegrally formed in one part. The side section not formed by the flangesection may, for example, be formed by the bearing section. Due to theuse of the flange section for forming one of the side sections of thereception recess, as compact as possible a design of the axle drive maybe achieved in that the flange section that is anyway required forconnecting the electric motor may also be used to nest the housing andto enable a space-saving arrangement of the brake disk.

In some embodiments, the brake may comprise a brake caliper that may befastened to, in particular floatingly supported at, an outer side of thehousing. In this respect, the fastening to an outer side of the housingmay in particular enable a simple and fast assembly of the brake at theaxle drive that may thereupon, for example as a complete unit fortransmitting drive power to the vehicle axle, be connected to orinstalled into an axle housing.

The brake caliper of the brake and the reception recess of the housingmay be arranged diametrically opposite one another with respect to thedriven shaft. In this respect, the axle drive may be configured to beinstalled in the vehicle such that the brake caliper is arranged beneaththe driven shaft and the reception section is arranged above the drivenshaft. The brake caliper may in particular be arranged in asubstantially straight line vertically beneath the reception section inthe assembled state of the axle drive. The brake caliper or the brakemay thereby also be easily accessible from below in the assembled stateof the axle drive in order, for example, to service the brake or toreplace components, in particular the brake disk, if necessary.

In some embodiments, the axle drive may be configured such that thebrake disk may be removed without dismantling or opening the housing inthat the brake caliper is first released from the housing and is thenradially removed from the housing with respect to the driven shaft andthe brake disk is released from the second end of the driven shaft andis then radially removed from the reception recess with respect to thedriven shaft. In such embodiments, the brake disk may, for example, beremoved to replace a worn brake disk without closures or flange sectionsof the housing having to be released or the housing having to be removedfrom an axle housing to which the axle drive may be connected in theassembled state.

The brake caliper may in this respect be fastened to an outer side ofthe housing. The brake caliper may in particular be arranged verticallydownwardly disposed in the assembled state of the axle drive such thatthe brake caliper may be accessible in a simple manner and may beradially removed from the housing with respect to the driven shaft. Inthis respect, the brake caliper may in particular be arrangedperpendicular below the driven shaft. Alternatively thereto, the brakecaliper may, however, also be attached laterally and rotated by up to90°, preferably by up to 45°, in comparison with an arrangement that isperpendicular with respect to the driven shaft. Here, too, the brakecaliper may engage around a radially outwardly disposed section of thebrake disk and may be easily accessible from the outside to be able tobe removed in the radial direction with respect to the driven shaft.Whereas, in the assembled state, the brake caliper may so-to-sayradially outwardly block the reception recess with respect to the driveshaft or with respect to the driven shaft, the brake disk may beaccessible after such a simple removal of the brake caliper and,possibly after a slight axial offset within the reception recess, thebrake disk may without problem be radially removed from the receptionrecess with respect to the drive shaft or vertically downwardly removedfrom the reception recess. In the same way, a brake disk that has, forexample, been replaced may then first be connected to the driven shaftagain, whereupon the brake caliper may also be fastened to the housingagain.

In some embodiments, provision may further be made that the spacing ofthe side sections of the reception recess is dimensioned such that thebrake disk may be completely removed from the driven shaft or a holderof the driven shaft in an axial direction with respect to the drivenshaft. Such a spacing of the side sections may consequently make itpossible, for example, to remove fastening means by which the brake diskis fastened to a holder of the driven shaft or to the driven shaftitself for a rotationally fixed connection to the driven shaft to beable to release the brake disk from the driven shaft or its holder inthe axial direction and thereupon to be able to freely remove the brakedisk from the reception recess in the radial direction. This may inparticular enable a simple and fast assembly and dismantling of thebrake disk when the axle drive is completely installed and is, forexample, connected to an axle housing of a vehicle.

In some embodiments, the output section of the drive shaft and the inputsection of the driven shaft are coupled drive-wise to one another via atleast one spur gear set. In this respect, the spur gear set may inparticular be arranged within a housing of the axle drive. Such a spurgear set may enable as compact and direct a transmission as possible ofthe drive power from the drive shaft to the driven shaft, wherein areduction or a slowing down of the rotational speed from the drive shaftto the driven shaft may in particular take place by a suitable selectionof the gear wheels of the spur gear set.

Provision may be made that the drive shaft and the driven shaft arerotationally fixedly connected to a respective gear wheel of the spurgear set, wherein the housing may have an assembly opening through whichthe driven shaft may be introduced into the housing in axial direction,and wherein the housing may have an insertion opening through which thegear wheel of the driven shaft may be inserted into the housing fromradial direction with respect to the driven shaft. The gear wheels mayin this respect be configured as separate components. In general,however, at least one of the gear wheels, in particular the gear wheelconnected to the drive shaft, may also be integrally formed at the driveshaft or the driven shaft.

Since only the driven shaft, which is formed with a relatively smallerextent in the radial direction, is to be inserted through the assemblyopening, the assembly opening may, for an axial insertion of the drivenshaft, be formed with as small a diameter as possible and at most aslightly larger diameter than the diameter of the driven shaft to beable to arrange and support the driven shaft as precisely as possible inthe inner space of the housing and in particular in a bearing sectionintegrally formed in one part. In contrast, the gear wheel of the drivenshaft having a relatively larger radial extent may be introduced fromthe radial direction, in particular before the introduction of thedriven shaft, through the insertion opening into an inner space of thehousing. The driven shaft may thereupon, for example, be guided from theaxial direction through an opening in a central section of the gearwheel and may be rotationally fixedly connected to the gear wheel withinthe housing, for example, by shrinking or thermal expansion. Provisionmay also be made to rotationally fixedly couple the gear wheel to thedriven shaft by means of a form fit and/or friction locking, for whichpurpose the gear wheel may in particular be connected to the drivenshaft via a splined shaft connection. The insertion opening may inparticular be arranged vertically downwardly disposed in a fullyassembled state of the axle drive.

In this respect, the introduction of the gear wheel from the radialdirection through the insertion opening in particular makes it possibleto insert a gear wheel having a relatively large diameter into the innerspace of the housing without having to form an opening having asimilarly large radial extent for this purpose to be able to insert thegear wheel from the axial direction. Rather, the insertion opening may,for example, be formed as a shallow slit and the assembly opening may beformed with a small diameter such that a simple assembly may be achievedby these openings without weakening the housing in a relevant manner.Furthermore, gear wheels having relatively large diameters may also beintroduced through such an insertion opening to be able to form the spurgear set as a speed reduction stage and to enable a reduction or aslowing down of the rotational speed from the drive shaft to the drivenshaft.

The housing may further have a fastening recess, wherein the insertionopening is formed in a base of the fastening recess, said base beingradially inwardly offset relative to an outer border of the fasteningrecess with respect to the driven shaft. A cover may further be providedto close the insertion opening, said cover being attachable to theinsertion opening and consequently to the base of the fastening recess.In this respect, the cover may in particular be configured such that,when it closes the insertion opening, it is arranged radially inwardlyoffset relative to the border of the insertion opening. In this respect,the cover preferably does not extend radially outwardly beyond theborder of the fastening recess. The cover may thus be arranged radiallyinwardly protected by the further parts of the housing, in particular abearing section, and may accordingly not be arranged in an exposedmanner such that the cover may be protected from external influences andpossible damage during travel, which is in particular important for adownwardly disposed orientation of the insertion opening in theassembled state.

Consequently, such a radially inwardly offset cover enables a verycompact design and simple assembly of an axle drive comprising twoshafts that are aligned in parallel with one another and that areconnected to one another via a spur gear set without the openingsrequired for the assembly resulting in a weakening of the housing.

In this regard, the invention also relates independently of an axledrive comprising a brake, in particular having a parking brake, to anaxle drive for a vehicle comprising at least one drivable vehicle axleoriented transversely to a longitudinal direction of the vehicle, saidaxle drive comprising a drive shaft that extends in parallel with thelongitudinal direction and that is configured to receive drive powerfrom a motor, in particular an electric motor, at an input section andto output said drive power at an output section; and a driven shaft thatextends offset from the drive shaft in parallel with the longitudinaldirection of the vehicle between a first end and a second end oppositethereto and that is configured to receive drive power from the outputsection of the drive shaft at an input section and to output said drivepower to the vehicle axle via a bevel gear arranged at the first end,wherein the drive shaft and the driven shaft are coupled drive-wise toone another via a spur gear set, wherein the axle drive has a housinghaving an assembly opening through which the driven shaft may be axiallyintroduced into an inner space of the housing, and wherein the housinghas an insertion opening through which a gear wheel of the spur gear setrotationally fixedly connectable to the driven shaft may be radiallyintroduced into the inner space of the housing with respect to thedriven shaft, wherein the insertion opening is formed in a base of afastening recess of the housing, said base being radially inwardlyoffset relative to an outer border of the fastening recess with respectto the driven shaft, and wherein the housing has a cover for theinsertion opening, said cover being arranged radially inwardly offsetrelative to the border of the insertion opening with respect to thedriven shaft when the cover closes the insertion opening.

Embodiments of the axle drive disclosed here comprising a brake are alsopossible for an axle drive that is generally independent thereof andthat has a radially inwardly arranged cover for closing an insertionopening.

In some embodiments, generally with respect to the disclosed axle drivecomprising a brake, the output section of the drive shaft and the inputsection of the driven shaft may be coupled drive-wise to one anothersuch that a speed reduction results on the transmission of the drivepower from the drive shaft to the driven shaft. A rotation of the driveshaft may consequently be transmitted slowed down to the driven shaft inorder in particular also to be able to use fast-rotating electricmotors. Due to such a speed reduction, the torque required to drive thevehicle axle may be applied, on the one hand, while, on the other hand,due to the brake disk that equally rotates at a reduced rotationalspeed, vibrations of the brake disk and an associated noise formationmay be minimized or avoided.

The axle drive may be configured to be installed in the vehicle suchthat the drive shaft is arranged vertically offset from the drivenshaft. In this respect, the axle drive may in particular first becompletely pre-assembled or assembled and may then be installed as aunit into an axle housing or fastened to an axle housing. In thisrespect, the drive shaft may in particular extend vertically above thedriven shaft to enable access from below to the brake disk arranged atthe driven shaft.

In some embodiments, the axle drive may further comprise a ring gearthat meshes with the bevel gear. Due to such a ring gear, a deflectionof the rotation of the bevel gear about the driven shaft aligned inparallel with the longitudinal direction of the vehicle into a rotationabout the vehicle axle oriented transversely to this longitudinaldirection may in particular be achieved to be able to drive the vehicleaxle.

In this respect, the axle drive may further comprise at least onehalf-shaft of the vehicle axle, wherein the ring gear may berotationally fixedly coupled to the half-shaft. Due to such a coupling,the rotation transmitted from the bevel gear to the ring gear may thusbe directly conducted to the vehicle axle. In this respect, provisionmay generally be made that two half-shafts of the vehicle axle arerotationally fixedly connected to the ring gear such that wheelsarranged at respective ends of the half-shafts may be uniformly drivenby means of the axle drive. Alternatively thereto, provision may be madethat the axle drive drives only one of the half-shafts and a furtheraxle drive having a further electric motor is provided for driving theother half-shaft such that, by a suitable control of the electricmotors, different rotational speeds of wheels arranged at the ends ofthe half-shafts may in each case be generated in order, for example, tofacilitate the driving through of a bend. In this respect, saidhalf-shafts may in particular be formed in multiple parts or at least intwo parts, wherein a first part may be directly connected to the ringgear, while a second part of the half-shaft may, for example, berotationally fixedly connected to the first part via a flange. The firstpart may in this respect further extend within a housing section of ahousing of the axle drive. Alternatively thereto, the axle drive mayfurther comprise a differential for distributing at least a respectiveportion of the drive power to two half-shafts of the vehicle axle,wherein the ring gear may be rotationally fixedly coupled to thedifferential. Driven shafts of the differential may in this respect berotationally fixedly connected to a respective half-shaft of the vehicleaxle, for example via a flange, or may correspond to the half-shafts.Furthermore, the differential may be arranged in a housing section thatis included by a housing of the axle drive or that may be connected tosuch a housing. Due to such a differential, a proportional distributionof the drive power to the half-shafts and to wheels associated therewithmay, for example, take place to enable a faster rotation of an outwardlydisposed wheel during the driving through of a bend.

The invention will be explained purely by way of example in thefollowing with reference to embodiments and to the drawing.

There are shown:

FIG. 1 a representation of an axle drive with a brake;

FIGS. 2A and 2B a schematic representation of an embodiment of the axledrive and a schematic representation of such an axle drive in connectionwith a vehicle axle driven by the axle drive; and

FIGS. 3A and 3B a schematic representation of a further embodiment ofthe axle drive and a schematic representation of two such axle drives,in each case in connection with a respective half-shaft of a vehicleaxle individually driven by the respective axle drive.

The Figures each show an axle drive 11 for driving a vehicle axle 13oriented transversely to a longitudinal direction L of a vehicle, notshown. This axle drive 11 in this respect has a drive shaft 19 that isaligned in parallel with the longitudinal direction L and that iscoupled via a spur gear set 69 to a driven shaft 27 that likewiseextends in parallel with the longitudinal direction L and offset fromthe drive shaft 19 (cf. FIG. 1 and the schematic representations inparticular of FIGS. 2A and 3A).

The drive shaft 19 comprises an input section 21 that forms an endsection of the drive shaft 19 and that is configured to receive drivepower from an electric motor 23 (cf. in particular FIGS. 2A and 3A). Theelectric motor 23 (having a stator and a rotor) is oriented coaxially tothe drive shaft 19. The drive shaft 19 further has an output section 25at which a gear wheel 71 is arranged that is rotationally fixedlyconnected to the drive shaft 19, that meshes with a gear wheel 73arranged at an input section 33 of the driven shaft 27, and that,together with said gear wheel 73, forms said spur gear set 69 fortransmitting drive power from the drive shaft 19 to the driven shaft 27.

A bevel gear 35 that meshes with a ring gear 87 is further arranged at afirst end 29 of the driven shaft 27 to transmit drive power to thevehicle axle 13 and to deflect it in so doing. As can be seen from FIGS.2A and 2B or 3A and 3B and as explained in more detail below, the ringgear 87 may in this respect be rotationally fixedly connected to ahalf-shaft 15 or 17 of the vehicle axle 13 in order to transmit thedrive power directly to a wheel arranged at the respective half-shaft 15or 17, or the ring gear 87 may be rotationally fixedly coupled to adifferential cage 91 of a differential 89 by means of which the drivepower transmitted to the ring gear 87 may be proportionally distributedto the two half-shafts 15 and 17.

The drive shaft 19 and the driven shaft 27 are, at least partly,arranged within a housing 41, wherein in particular the output section25 of the drive shaft 19 and the input section 33 of the driven shaft 27and accordingly also the spur gear set 69 are arranged in an inner space49 of the housing 41 (cf. FIG. 1 ). In this respect, the housing 41 hasa bearing section 43 which is integrally formed in one part, which ismanufactured as a single bonded component, and at which bearings 45, 46,and 47 for the drive shaft 19 or the driven shaft 27 are supported. Dueto this support of the bearings 45, 46, and 47 at the bearing section 43integrally formed in one part, the respective bearings 45 and 46 of thedrive shaft 19 or the bearings 47 of the driven shaft 27 may be orientedexactly in alignment with one another to be able to handle the highrotational speeds, in particular of the drive shaft 19, generated by afast-rotating electric motor 23 and to be able to use such compactelectric motors 23.

While the bearings 47 of the driven shaft 27 and the bearing 46 of thedrive shaft 19 are supported directly at the bearing section 43, thebearing 45 of the drive shaft 19 arranged in the region of the inputsection 21 is directly supported at a flange section 63 and isindirectly supported at the bearing section 43 via the flange section63. This flange section 63 in particular serves to connect an electricmotor 23 (cf. FIGS. 2A to 3B) and may be centered at an outer diameterin the bearing section 43. In this respect, the flange section 63 isinserted into an opening of the bearing section 43 such that it isradially arranged between the bearing 45 and the bearing section 43 withrespect to the drive shaft 27 and in this respect radially directlyadjoins the bearing 45, on the one hand, and the bearing section 43, onthe other hand. The flange section 63 and the bearing section 43 mayfurther be precisely aligned with one another by a suitable fitselection or tolerance selection, wherein the flange section 63 may befastened to the bearing section 43 by means of a plurality of fasteningmeans 113, in particular screws. Despite the merely indirect support ofthe bearing 45 at the bearing section 43, the bearings 45 and 46 maythereby be positioned exactly in alignment with one another to ensure aprecise alignment of the drive shaft 19 in parallel with thelongitudinal direction L of the vehicle. Furthermore, due the precisealignment and centering of the flange section 63 in the bearing section43, an exact alignment of the electric motor 23 via the flange section63 for connection to the input section 21 of the drive shaft 19 may beensured.

The gear wheels 71 and 73 of the drive shaft 19 or the driven shaft 27are here configured such that a reduction or a slowing down of therotational speed of the drive shaft 19 takes place at the spur gear set29 and the driven shaft 27 rotates slowed down with respect to the driveshaft 19. In particular on the use of fast-rotating electric motors 23for transmitting drive power to the input section 21 of the drive shaft19, the necessary torques for driving the vehicle axle 13 may beachieved by such a speed reduction stage.

Furthermore, the inner space 49 of the housing 41 forms a common oilchamber 51 such that the bearings 45, 46, and 47 may be lubricatedwithout a pump, on the one hand, and a larger surface for leading offwaste heat generated by the fast-rotating drive shaft 19 may beprovided, on the other hand. Waste heat generated by the drive shaft 19may thus also be led off in a region of the driven shaft 27 thatgenerates a smaller amount of waste heat due to its slowed-downrotation. This common oil chamber 51 may in particular furthercommunicate with an axle chamber 117, into which the bevel gear 35projects, via the first end 29 of the driven shaft 27 at which the bevelgear 35 is arranged. This may enable a further increase in the radiationsurface for leading off waste heat and a lubrication of the axle drive11 via a gear drive and a wiper in a reservoir without a pump beingnecessary. In this respect, the axle chamber 117 may in particular besurrounded by an axle chamber housing section 115 that is connected tothe bearing section 43 by means of respective fastening means 113. Thisaxle housing section 115 may thus be part of the housing 41 of the axledrive 11 such that the total axle drive 11 or its housing 41 may bepre-assembled and connected as a complete unit to an axle housing 53 ofthe vehicle axle 13 (cf. also FIGS. 2B and 3B).

As FIG. 1 further shows, the housing 41 has an assembly opening 75 whichis formed at the bearing section 43 and through which the driven shaft27 may be inserted into the inner space of the housing 41 from the axialdirection. In order also to be able to insert the gear wheel 73, whichis formed with a relatively large diameter, into the inner space of thehousing 41 and to be able to connect it to the driven shaft 27, thehousing 41 has an insertion opening 77 at a lower side in the assembledstate of the axle drive 11, through which insertion opening 77 the gearwheel 73 may be radially inserted into the inner space 49 of the housing41 with respect to the driven shaft 27. This makes it possible, duringan assembly of the axle drive 11, to first insert the gear wheel 73 fromthe radial direction through the insertion opening 77 into the innerspace 49 and then to insert the driven shaft 27 with an exact fit fromthe axial direction through the assembly opening 75 into the inner space49 and to precisely arrange said driven shaft 27 between the bearings47. The driven shaft 27 may then be rotationally fixedly connected tothe gear wheel 73, for example, by shrinking or thermal expansion. Aform-fitting and/or friction-locked connection, in particular via asplined shaft connection, may also be provided. The bevel gear 35 may inparticular already be connected to the driven shaft 27 or formed in onepart with the driven shaft 27 before the insertion of the driven shaft27 into the inner space of the housing 41.

To be able to close the insertion opening 77 after the insertion of thegear wheel 73, the housing 41 has a cover 79 that is fastened to a base85 of a fastening recess 81 by means of a plurality of fastening means113. Due to the attachment of the cover 79 in the fastening recess 81,the cover 79 is radially inwardly offset relative to an outer border 83of the fastening recess 81 with respect to the driven shaft 27 and inthis respect does not project radially outwardly beyond the border 83.In this way, the cover 79 is protected from external influences anddamage, in particular during a trip with the vehicle. The assemblyopening 75 and the insertion opening 77, which may be closed by thecover 79, thus enable a simple and convenient assembly of the axle drive11, wherein a very compact design of the axle drive 11 may be achievedby the two-sided insertion of the driven shaft 27 and the gear wheel 73.Due to the radially inward offset of the cover 79, a possible weakeningof the housing 41 by the insertion opening 77 arranged at the lower sideof the housing 41 or by a cover 79 positioned elsewhere and in anexposed manner may be reliably prevented.

While the common oil chamber 51 already mentioned communicates with theaxle chamber 117 through the first end 29 of the driven shaft 27, whichexits the housing 41, and the bevel gear 35 arranged thereat, the drivenshaft 27 projects out of the housing 41 with a second end 31 oppositethe first end 29 in a manner sealed by seals 111. At this second end 31,a brake disk 39 of a brake 37 is rotationally fixedly connected to thedriven shaft 27 via a holder 67. Due to the seal 111, the brake disk 39in this respect runs completely dry such that the brake 37 is designedas a dry brake. The brake disk 39 is further arranged between the inputsection 21 of the drive shaft 19 and the input section 33 of the drivenshaft 27 (and thus axially between the electric motor 23 and the spurgear 69) with respect to the longitudinal direction L such that the axledrive 11 does not experience any relevant extension along thelongitudinal direction L due to the configuration with the brake disk39. As can be seen from the Figures, a section of the drive shaft 19extends radially offset from the brake disk 69.

The brake 37 further has a brake caliper 65 that is fastened in afloatingly supported manner to an outer side of the housing 41 by beingscrewed to the housing 41 in parallel with the longitudinal direction L.In this respect, the brake caliper 65 is in particular arranged at alower side of the housing 41 in an assembled state of the axle drive 11such that, after a loosening of the screw connection, the brake caliper65 may be removed in a simple manner in the radial direction withrespect to the driven shaft 27 in order to enable access to the brakedisk 39.

The brake 37 in this respect acts as a parking brake and is provided toreliably secure the vehicle against rolling away when stationary by anengagement of the brake caliper 65 into the brake disk 39. In addition,the brake 37 also serves to provide an emergency braking function. Forthis purpose, the brake caliper 65 may be actively brought out ofengagement with the brake disk 39 during the travel, wherein it isconfigured to automatically come into engagement with the brake disk 39and to brake the vehicle on a failure or a disturbance of the pressurerequired for this purpose.

While the brake disk 39 is arranged completely outside the housing 41 orits inner space 49, the housing 41 forms a reception recess 57 that isbounded in the axial direction by two side sections 59 and 61 and thatsurrounds a peripheral region 55 of the brake disk 39 that is dependenton the respective rotational position of the brake disk 39. These sidesections 59 and 61 extend radially outwardly and are axially connectedto one another radially inside with respect to the drive shaft 19. Inthis respect, the side section 59 is formed by the flange section 63connected to the bearing section 43, whereas the side section 61 isformed by the bearing section 43 itself. The side section 59 extendsoutwardly substantially in a straight line in the radial direction withrespect to the drive shaft 19, while the side section 61 has a structureand the spacing in the axial direction between the side section 61 andthe brake disk 39 changes in the radial direction. Accordingly, thereception recess 57 is substantially U-shaped, wherein the side sections59 and 61 do not necessarily form rectilinear limbs of this U-shapedreception recess 57.

Due to the reception recess 57, a high integration of the brake 37 or ofits brake disk 39 in the axle drive may be achieved. The nested designof the housing 41 makes it possible to arrange the peripheral region 55of the brake disk 39 in a section of the axle drive 11 that, due to thespur gear set 69 and the flange section 63, anyway requires a certainextent of the axle drive 11 in the radial direction with respect to thedrive shaft 19 or the driven shaft 27. Since the extent of theperipheral section 55, which is surrounded by the side sections 59 and61, at least approximately corresponds to the radius of the brake disk39 in the radial direction, the configuration of the axle drive 11 withthe brake 37 or the brake disk 39 only requires a minimal additionalextent of the axle drive 11 of at most approximately one radius of thebrake disk 39 in the radial direction. In the present case, this radialinstallation space is, in contrast, also already occupied by the gearwheel 73 of the driven shaft 27 such that the configuration of the axledrive 11 with the brake disk 39 substantially does not result in anadditional extension of the axle drive 11 in the radial direction. Theaxle drive 11 may thereby in particular be equipped with a parking brakefunction and/or an emergency brake function in a very space-savingmanner.

In the longitudinal direction L, the flange section 63 required forconnecting the electric motor 23 is arranged only slightly axiallyoffset to provide a free space or the reception recess 57 for the brakedisk 39. The configuration of the axle drive 11 with a brake disk 39thus also requires only a very small additional extension of the axledrive 11 in the longitudinal direction L such that this nested design ofthe axle drive 11 or of its housing 41 may enable an axle drive 11 ofcompact design as desired.

Furthermore, the spacing of the side sections 59 and 61 in the axialdirection may be dimensioned such that the brake disk 39 may becompletely released from the holder 67 in the axial direction. In order,for example, to be able to replace the brake disk 39, the brake caliper65 may consequently first be released from the housing 41 and removed inthe radial direction. Thereupon, the fastening means 113 by which thebrake disk 39 is fastened to the holder 76 may also be released andremoved, whereupon the brake disk 39 may be removed from the holder 76or the driven shaft 27 in the axial direction and may be removed fromthe reception recess 57 in the radial direction. The axle drive 11 isconsequently configured such that the brake disk 39 may be removedwithout dismantling or opening the housing 41 or without removingindividual housing parts.

Furthermore, due to the reduction of the rotational speed from the driveshaft 19 to the driven shaft 27 taking place at the spur gear set 69,the brake disk 39 also rotates at a reduced rotational speed withrespect to the drive element 19 during a journey of the vehicle. Due tothis reduced rotational speed, strong vibrations of the brake disk 39may in particular be prevented from forming such that a noise formationor possible instabilities of the axle drive 11 may be avoided on the useof fast-rotating electric motors 23 for driving the drive shaft 19.

FIGS. 2A and 2B schematically show an embodiment of the axle drive andits connection to an axle housing 53. In this respect, an electric motor23 is connected to the flange section 63, said electric motor 23outputting drive power to the input section 21 of the drive shaft 19that transmits the drive power at the output section 25 to the inputsection 33 of the driven shaft 27. The drive shaft 19 and the drivenshaft 27 are in this respect connected to one another via the spur gearset 69, wherein a reduction of the rotational speed from the drive shaft19 to the driven shaft 27 takes place by the gear wheels 71 and 73. Thebrake disk 39 is arranged at the second end of the driven shaft 27, saidbrake disk 39 being received outside the housing 41 of the axle drive 11in the reception recess 57 formed by the housing 41 and being part ofthe brake 37. The bevel gear 35, which meshes with the ring gear 87, isarranged at the first end 29 of the driven shaft 27 opposite the secondend 31.

In this embodiment, the ring gear 87 is rotationally fixedly connectedto a differential cage 91 of a differential 89 whose driven shafts arerotationally fixedly connected to a respective half-shaft 15 or 17 of avehicle axle 13. The balancing gears 93 of the differential 89 in thisrespect make it possible to proportionally transmit drive power receivedvia the bevel gear 35 and the ring gear 87 to the half-shafts 15 and 17.

As FIG. 2B shows, the housing 41 of the axle drive 11 may be connectedto the axle housing 53, wherein the axle drive 11 may in particularfirst be pre-assembled and may thereupon be inserted as a complete unitinto the axle housing 53. The vehicle axle 13 is in this respectconfigured as an outer planetary axle 107 and, at the ends of thehalf-shafts 15 and 17, has respective planetary gear sets 97 by means ofwhich the rotational speed of the half-shafts 15 and 17 is transmittedin a speed-reduced or slowed-down manner to a respective wheel hub 95for driving a wheel.

The reduction in speed in this respect takes place in that thehalf-shafts 15 and 17 are rotationally fixedly connected to a respectivesun gear 101 that is surrounded by a plurality of planet gears 103. Aring gear 99 arranged concentrically to and surrounding the sun gear 101is rotationally fixedly held, while the planet gears 103 rotate aboutaxles that are supported on a web 105 revolving around the sun gear 101.In this respect, the web 105 is rotationally fixedly connected to thewheel hub 95 such that the latter rotates at the rotational speed of theweb 105 that is reduced in comparison with the sun gear 101 or with arespective one of the half-shafts 13 and 15. In particular on the use offast-rotating electric motors 23, such outer planetary axles 107 mayalso be provided to further reduce the rotational speed and to increasethe torque.

In the embodiment shown in FIGS. 3A and 3B, instead of the differential89, only a ring gear 87 is provided that meshes with a bevel gear 35arranged at a second end of a driven shaft 27 and that is rotationallyfixedly connected to at least one half-shaft 15 or 17. As FIG. 3A shows,the ring gear 87 may in this respect be rotationally fixedly connectedto both half-shafts 15 and 17 in order to directly drive the totalvehicle axle 13.

Alternatively thereto, as illustrated in FIG. 3B, it is also possible toprovide a respective separate axle drive 11, having a separate electricmotor 23, for each half-shaft 15, 17 for driving the half-shafts 15 and17. In this respect, each of the half-shafts 15 and 17 is rotationallyfixedly connected to a ring gear 87 such that the electric motors 23 maydrive the half-shafts 15 and 17 individually or independently from oneanother. A drive power may thereby also be proportionally transmitted tothe two half-shafts 15 and 17 depending on the situation in order, forexample, to enable a faster rotation of a wheel rotating at the outsideon the driving through of a bend. The vehicle axle 13 is again providedas an outer planetary axle 107 having respective planetary gear sets 97,which act as reduction gear units, for transmitting the rotation to thewheels. In general, the axle drive 11 disclosed herein may, however, beprovided for driving vehicle axles 13 of any kind.

The axle drive 11 disclosed herein consequently enables a very compactdesign with a high integration of a brake 37, in particular a parkingbrake, and its brake disk 39 into the axle drive 11. Furthermore, theslowing down of the rotational speed from the drive shaft 19 to thedriven shaft 27 and to the brake disk 39 rotationally fixedly connectedthereto enables the use of fast-rotating and compact electric motors 23without the fast rotations resulting in strong vibrations of the brakedisk 39 that may possibly damage the axle drive 11 and result in astrong noise formation. The configuration of the axle drive 11 with ahousing 41, which has a bearing section 43 integrally formed in onepart, may furthermore enable an exact alignment of the bearings 45, 46,and 47 of the drive shaft 19 and of the driven shaft 27 to be able tohandle the high rotational speeds of a fast-rotating electric motor 23.

REFERENCE NUMERAL LIST

-   11 axle drive-   13 vehicle axle-   15 first half-shaft-   17 second half-shaft-   19 drive shaft-   21 input section of the drive shaft-   23 electric motor-   25 output section of the drive shaft-   27 driven shaft-   29 first end-   31 second end-   33 input section of the driven shaft-   35 bevel gear-   37 brake-   39 brake disk-   41 housing-   43 bearing section-   45 drive-side bearing of the drive shaft-   46 driven-side bearing of the drive shaft-   47 bearing of the driven shaft-   49 inner space of the housing-   51 common oil chamber-   53 axle housing-   55 peripheral region of the brake disk-   57 reception recess-   59 side section-   61 side section-   63 flange section-   65 brake caliper-   67 holder-   69 spur gear set-   71 gear wheel of the drive shaft-   73 gear wheel of the driven shaft-   75 assembly opening-   77 insertion opening-   79 cover-   81 fastening recess-   83 outer border of the fastening recess-   85 base of the fastening recess-   87 ring gear-   89 differential-   91 differential cage-   93 balancing gear-   95 wheel hub-   97 planetary gear set-   99 ring gear-   101 sun gear-   103 planet gear-   105 web-   107 outer planetary axle-   111 seal-   113 fastening means-   115 axle chamber housing section-   117 axle chamber-   L longitudinal direction of the vehicle

What is claimed is:
 1. An axle drive for a vehicle comprising at leastone drivable vehicle axle oriented transversely to a longitudinaldirection of the vehicle, said axle drive comprising a drive shaft thatextends in parallel with the longitudinal direction of the vehicle andthat is configured to receive drive power from an electric motor at aninput section and to output said drive power at an output section; adriven shaft that extends offset from the drive shaft in parallel withthe longitudinal direction of the vehicle between a first end and asecond end opposite thereto and that is configured to receive drivepower from the output section of the drive shaft at an input section andto output said drive power to the vehicle axle via a bevel gear arrangedat the first end; and a brake, in particular a parking brake, having abrake disk that is arranged at the second end of the driven shaft andthat is arranged between the input section of the drive shaft and theinput section of the driven shaft with respect to the longitudinaldirection of the vehicle.
 2. The axle drive in accordance with claim 1,wherein the axle drive further comprises a housing in which the driveshaft and the driven shaft are received, wherein the output section ofthe drive shaft and the input section of the driven shaft are arrangedwithin the housing.
 3. The axle drive in accordance with claim 2,wherein the housing has a bearing section integrally formed in one partor is formed by a bearing section which is integrally formed in onepart, wherein bearings for supporting at least one of the drive shaftand/or the driven shaft are supported at the bearing section.
 4. Theaxle drive in accordance with claim 2, wherein an inner space of thehousing defines a common oil chamber for the drive shaft and the drivenshaft.
 5. The axle drive in accordance with claim 4, wherein the axledrive is configured such that the common oil chamber communicates withan axle chamber into which the bevel gear projects.
 6. The axle drive inaccordance with claim 2, wherein the brake disk is arranged outside thehousing.
 7. The axle drive (11) in accordance with claim 6, wherein thehousing extends around the brake disk such that it axially surrounds aperipheral region of the brake disk at both sides.
 8. The axle drive inaccordance with claim 7, wherein a reception recess for the brake diskis formed at the housing, said reception recess having two side sectionsthat face radially outwardly with respect to the drive shaft and thatare axially connected to one another radially inside, wherein saidperipheral region of the brake disk is arranged between the sidesections.
 9. The axle drive in accordance with claim 8, wherein thereception recess is at least partly formed by a flange section of thehousing, said flange section being provided for fastening the electricmotor to the housing.
 10. The axle drive in accordance with claim 2,wherein the brake comprises a brake caliper that is fastened to, anouter side of the housing.
 11. The axle drive in accordance with claim10, wherein the brake caliper of the brake and the reception recess ofthe housing are arranged diametrically opposite one another with respectto the driven shaft.
 12. The axle drive in accordance with claim 10,wherein the axle drive is configured such that the brake disk can beremoved without dismantling or opening the housing in that the brakecaliper is first released from the housing and is then radially removedfrom the housing with respect to the driven shaft and the brake disk isreleased from the second end of the driven shaft and is then radiallyremoved from the reception recess with respect to the driven shaft. 13.The axle drive in accordance with claim 8, wherein the spacing of theside sections of the reception recess is dimensioned such that the brakedisk can be completely removed from the driven shaft or a holder of thedriven shaft in an axial direction with respect to the driven shaft. 14.The axle drive in accordance with claim 1, wherein the output section ofthe drive shaft and the input section of the driven shaft are coupleddrive-wise to one another via at least one spur gear set.
 15. The axledrive in accordance with claim 14, wherein the drive shaft and thedriven shaft are rotationally fixedly connected to a respective gearwheel of the spur gear set, wherein the housing has an assembly openingthrough which the driven shaft can be introduced into the housing inaxial direction, and wherein the housing has an insertion openingthrough which the gear wheel of the driven shaft can be inserted intothe housing from radial direction with respect to the driven shaft. 16.The axle drive in accordance with claim 15, wherein the insertionopening is formed in a base of a fastening recess of the housing, saidbase being radially inwardly offset relative to an outer border withrespect to the driven shaft.
 17. The axle drive in accordance with claim1, wherein the output section of the drive shaft and the input sectionof the driven shaft are coupled drive-wise to one another such that aspeed reduction results on the transmission of the drive power from thedrive shaft to the driven shaft.
 18. An The axle drive in accordancewith claim 1, wherein the axle drive is configured to be installed inthe vehicle such that the drive shaft is arranged vertically offset fromthe driven shaft.
 19. The axle drive in accordance with claim 1, whereinthe axle drive further comprises a ring gear that meshes with the bevelgear.
 20. The axle drive in accordance with claim 19, wherein the ringgear is rotationally fixedly coupled to a half-shaft of the vehicle axleor to a differential for distributing at least a respective portion ofthe drive power to two half-shafts of the vehicle axle.
 21. (canceled)